150 



PROCEEDINGS OF THE NATIONAL MUSEVM. 



vor„ sr 



The sperm ducts (fig. 4) are slender, much contorted ducts, of which 

 those of one side unite posterior to the septum, which we have as- 

 sumed may represent the fused septa 9/10, 10/11, and 11/12. From 

 the place of union the combined duct has a fairly direct course to 

 the spermiducal pore on the anterior part of 13. The pores are 

 anterior to the place of union of the septum 12/13 with the body 

 wall. There are no prostatic nor atrial modifications of the sperm 

 ducts, nor any development of papillae in connection with the pores. 

 The presence of abundant sperm cells gives evidence of sexual 

 maturity. 



We have found nothing in the literature on Moniligastridae which 

 indicates the presence of sperm sacs in addition to the sperm vesicles, 



yet such organs are clearly 



^^^^-^^^^1^ 



present in the species under 

 discussion. These organs are 

 so interesting in character and 

 the relationships which they 

 suggest are of such importance 

 that a somewhat detailed de- 

 scription is desirable. We use 

 the term spernv vesicles for 

 the chambers which inclose the 

 spermaries and the spermidu- 

 cal funnels and which are 

 called testikelblasen by 

 Michaelsen (1900:9). We 

 use the term sperm sacs for the 

 storage chambers which are 

 contained in somites adjacent 

 to the testicular somites while 

 communicating with the latter 

 b}'^ openings through the inter- 

 vening septa. Michaelsen 

 calls them samensacken. The sperm vesicles of either side are in in- 

 timate contact and suspended by what is assumed to be a compound 

 septum representing septa 9/10, 10/11, and probably 11/12. The 

 spermaries of either side are borne by the anterior walls of the cor- 

 responding sperm vesicles which presumably represent septa 9/10 

 and 10/11, respectively (fig. 3). Parts of the posterior walls of the 

 sperm vesicles, presumably septa 10/11 and 11/12, have a thickened 

 ciliated epithelium which is much folded and constitutes the sperm- 

 iducal funnels. Numerous small, thin-walled sacs containing mature 

 sperm cells (fig. 5) project posteriorly from the depressions between 

 these folds and occupy space in the somites 11 and 12, although 

 their cavities communicate with the preceding somites. These sacs 



FiQ. 4.— Syngenodrilus lamuensis. Section 



THEOUGH SPERM VESICLES NEAR LATERAL WALLS. 



X35. ft, Heart; n, NEPHRiDroM; s d, sperm 

 duct; a v, sperm vesicles. 



